This example displays a multi-series line chart using a dataset of 150 samples, plotting three quantitative variables—Sales, Profit, and Expenses—against a sequential Sample number. It builds the visualization with React and D3 v7, using `d3.csv` to fetch remote data and `d3.scaleLinear` for axes. The SVG rendering uses `d3.line` generators to create three separate polylines, each with a distinct stroke color, and includes y-axis gridlines, axis labels, a title, and a legend. The React integration is minimal, relying on `d3.select('#root').append('svg')` to attach the chart directly to the DOM root.